EFFECT OF LOW-FREQUENCY VIBRATIONS ON SPECKLE INTERFEROMETRY FRINGES

The effects of low-frequency vibrations on speckle correlation fringes have been investigated. The relatively short capture time of the came ra in the low-frequency case may yield usable fringe contrast in spite of vibration. It has been shown that the fringes also shift due to th e vibration. The study is in agreement with experimental observations of good-contrast correlation fringes even if the object is not on a vi bration-isolated table. Some such experimental observations are also p resented. (C) 1998 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(98)03605-8].